The present invention relates to a vehicle control unit and a vehicle control method, and more particularly to a vehicle control unit and a vehicle control method for controlling a vehicle having a battery which supplies electric power to electric equipments of the vehicle and an alternator which generates the electric power and charges the battery when an engine of the vehicle is operated and an economical running control section operable to perform an economical running in which the engine is automatically stopped when the vehicle is in a predetermined engine stopping condition and the engine is automatically restarted when the vehicle is in a predetermined engine restarting condition.
There are vehicles on which an economical running system is installed. The economical running system is operable to perform the economical running in which the engine is automatically stopped when the vehicle is in a predetermined engine stopping condition and the engine is automatically restarted when the vehicle is in a predetermined engine restarting condition.
In addition, there are vehicles on which a plurality of electric equipments is installed. The electric equipments include accessories such as an on-board car audio system, and safety system units such as an ABS (Anti-Lock Braking System) for preventing the car from slip by sustained wheel-locking when the vehicle is suddenly braked or the vehicle is braked on a slippery road surface, a braking assist system for assisting a braking force so as to obtain a strong braking force when the vehicle is suddenly braked, and a pre-crash safety system in which a distance to an object from the vehicle is measured by a radar and when a collision is inevitable, the auxiliary brake is applied and occupants of the vehicle are restrained by retracting the seatbelts before the collision occurs.
In the above related-art vehicle, there is a vehicle on which a power supply management system is installed. When a current value which is supplied to the electric equipments becomes insufficient, the power supply management system performs a feed limitation on the accessories so as to securely feed to the safety system in view of safety.
In the power supply management system, for example, the consumption of the electric power by the electric equipments is equally suppressed in order to reduce the consumption of the electric power when an economical running is performed in a case where the charged level of the battery is low or the economical running is performed a number of times (refer, for example, to Japanese Patent Publication No. 2004-106621). When the economical running is performed, an engine of the vehicle is activated in a case where an ignition switch is on, the vehicle is in idling-stop state, and a predetermined condition is established is performed.
When the electric equipments such as the accessories and safety system units are used for a long period of time in a state that the engine is stopped and the alternator generates no current since the economical running is performed, the available current value of the battery is surely at a lower level than before the economical running is performed. Therefore, the feed limitation on the accessories other than the safety system units easily occurs at all times depending on the condition of the battery when the vehicle is restored to the normal state from the economical running state.
Here, when a feed limitation on the accessories is implemented due to the current value supplied to the electric equipments becoming insufficient, since the available current value that can be supplied to the electric equipments from the battery cannot be calculated accurately, the current value that can be so supplied is estimated lower. Therefore, the feed limitation on the accessories is implemented more than actually necessary. By such a feed limitation, the feed on the accessory on which the feed limitation did not actually have to be performed may be limited. Then, there is a problem that a reproduction of musing was stopped while the user was listening thereto, the conveniences of the user being thereby damaged.